This application claims priority to Japanese patent application numbers 2000-091138 filed Mar. 29, 2000, 2000-122912 filed Apr. 24, 2000, and 2000-349401 filed Nov. 16, 2000, under 35 USC 119.
1. Field of the Invention
The present invention relates to a method and apparatus for bringing a contactor into electrical contact with a projection electrode of a semiconductor device in a semiconductor device inspection equipment.
2. Prior Art
Generally, a semiconductor device such as an integrated circuit (referred to as xe2x80x9cICxe2x80x9d hereinafter) is electrically tested with the help of an electrical contact apparatus such as a probe card, an IC socket, or the like in order to examine if the circuit satisfactorily works according to a design specification as declared. Such an electrical test is usually carried out at several stages, for instance, at the stage where each semiconductor chip still stays on a semiconductor wafer, at the stage after the chip is cut off from the wafer, and at the stage after the chip is molded. The electrical contact apparatus is provided with a plurality of contactors which are pressed on a predetermined electrode of the chip during the test.
In case of a semiconductor device such as a Chip-Scale-Package (CSP), Ball-Grid-Array (BRG), or the like, using a hemispheric projection electrode (i.e. bump electrode) projecting on the side of the electrical contact apparatus as an electrode of the chip, it is a significant matter that the contactor never gives any damage to the projection electrode at the time of the electrical test of the chip. Especially, when the projection electrode is made of a soft material like solder, it has to be handled carefully. If the tip portion of the projection electrode is crushed, the height (projection height) of the projection electrode becomes different from electrode to electrode, so that at the time of the packaging the semiconductor chip, its projection electrode might often fail to rightly come in contact with the wiring arranged on the base plate.
As one technique for bringing the contactor into contact with the hemispherical projection electrode, it has been proposed to use a contactor formed in the shape of a pyramid, a cone, or a needle and to press the sharp tip portion thereof on the projection electrode.
As the other technique for bringing the contactor into contact with the hemispherical projection electrode, it has been proposed to use a contactor having a contact surface in the shape of a ring and to press that ring surface of the contactor on the projection electrode.
However, according to the one technique as describe above, since the tip portion of the contactor is pressed on the projection electrode of the semiconductor device side, the sharp tip portion of the contactor is stuck into the projection electrode, so that the tip portion of the projection electrode is damaged, and every projection electrode comes to have a different height.
On the other hand, according to the other technique as described above, since the ring-shaped contact surface of the contactor is pressed on the projection electrode on the side of the semiconductor device, the base portion of the projection electrode is crushed by the contact surface. As a result, the tip portion of the projection electrode might not be damaged, but every projection electrode still comes to have a different height.
Therefore, an object of the invention is to prevent the projection electrode of the semiconductor device from being damaged by the contactor as much as possible at the time of electrical test of the semiconductor device.
An electrical contact method according to the invention as used in a semiconductor device inspection equipment comprises the steps of preparing an electrical contact device having one or more pyramid-shaped contactors projecting toward the semiconductor device, and bringing the edge line or the slant surface of the above pyramid-shaped contactor into contact with the corresponding projecting electrode of the semiconductor device.
An electrical contact apparatus according to the invention as used in a semiconductor device inspection equipment includes a plate-like or filmy base and one or more pyramid-shaped contactors provided in correspondence with the projection electrode and projecting from the one surface side of the above base toward the semiconductor device. The above pyramid-shaped contactor is displaced, with respect to the corresponding projection electrode, in a predetermined direction in a plane parallel to the above base.
The slant surface indicates a slant surface portion other than the bottom surface of a polygonal pyramid. The edge line is defined as a boundary line formed between adjacent slant surfaces. Both of the slant surface and the edge line converges to the tip portion (apex) of the polygonal pyramid.
Since the edge line and the slant surface of the pyramid-shaped contactor make an angle with respect to the center axis of the projection electrode of the semiconductor device, neither the edge line nor the slant surface is pressed on the tip portion of the projection electrode, and they just make contact with the side portion of the projection electrode around and near the tip portion and pushes that contact portion in the state of keeping an angle with respect to the center axis as it is. Therefore, the projection electrode is prevented from being damaged due to the pressure applied by the pyramid-shaped contactor thereto.
The electrical contact apparatus may have one pyramid-shaped contactor against one projection electrode and, also, may have two or more pyramid-shaped contactors for one projection electrode.
A plurality of pyramid-shaped contactors may be arranged such that one of their edge lines or slant surfaces is brought into contact with one projection electrode. With this arrangement, any one of plural pyramid-shaped contactors surely comes in contact with the projection electrode regardless of any difference in size among the projection electrode.
If two or more pyramid-shaped contactors are provided for one projection electrode, these pyramid-shaped contactors provided for every projection electrode are arranged around the center axis of the projection electrode at angular intervals. With this arrangement, the projection electrode certainly comes in electrical contact with the pyramid-shaped contactor regardless of any difference in size among the projection electrode.
Plural pyramid-shaped contactors provided for every projection electrode can be arranged such that the edge line or the slant surface of each contactor comes in contact with the corresponding projection electrode when pressing the contactor on the projection electrode. This can be done, for instance, if each contactor is arranged to direct its edge line or slant surface toward the center axis of the corresponding projection electrode. With this arrangement, the projection electrode certainly comes in electrical contact with the edge line or the slant surface of the pyramid-shaped contactor.
The base can have an opening which is formed in an area inside the arrangement area of the plural pyramid-shaped contactors and is opened to at least the corresponding projection electrode. With this arrangement, since the opening of the base acts as an escape for the tip portion of the projection electrode to run, any damage due to collision between the tip portion of the projection electrode and the base can be prevented.
The electrical contact apparatus further includes one or more wiring portions provided on the base and electrically connected with the pyramid-shaped contactor. These wiring portions are connected with an electrical test circuit by a proper means such as a flat cable, a base plate, and so forth.
One or more pyramid-shaped contactors may be arranged on the base or on the seat portion arranged on the base.
The electrical contact apparatus further includes a base plate provided with a plurality of wiring portions respectively corresponding to the projection electrodes and being exposed at least in part to the one surface side of the base plate. This base has a pyramid-shaped auxiliary contactor formed on the other surface side, and the auxiliary contactor is brought into electrical contact with each corresponding wiring portion of the base plate and also with the pyramid-shaped contactor as well. With this arrangement, the electrical contact apparatus can be formed as a probe card or a socket for use in the electrical test of the semiconductor device.
The electrical contact apparatus further includes a frame arranged on the one surface side of the base plate, and the above base is fitted to the base plate such that the pyramid-shaped contactor is on the frame side.
The frame can have an opening for receiving the semiconductor device. With this, the electrical contact apparatus can be formed as a socket.
The electrical contact apparatus further includes a plate-like spacer arranged between the base and the base plate.
The electrical contact apparatus further includes a rubber plate arranged between the frame and the arrangement place of the auxiliary contactor arranged on the base. With this arrangement, the auxiliary contactor can be pressed on the wiring of the base plate by making use of elasticity of the rubber plate.
The electrical contact apparatus further includes a seat portion arranged on the base and the plural pyramid-shaped contactors corresponding to the projection electrode. These plural pyramid-shaped contactors can be arranged about the center axis of the corresponding projection electrode at angular intervals.
In the electrical contact apparatus as described above, the seat portion projects from the base and has an opening between adjacent pyramid-shaped contactors. Furthermore, the base can have a slit extending around the seat portion.